Rotary power hammer



I 15, 1964 E. L. ALLEN ETAL ROTARY POWER HAMMER Filed Aug. 8, 1965 3 Sheets-Sheet l INVENTORS EDWARD L. ALLEN ALBERT E GATT/KER, JR.

ATTORNEY Dec. 15, 1964 E. L. ALLEN ETAL 3,161,241

ROTARY POWER HAMMER Filed Aug. 8, 1963 3 Sheets-Sheet 2 INVENTORS EDWARD L. ALLEN ALBERQE GATT/KER, JR.

@M UTA/2M6" ATTORNEY Dem 1964 E. ALLEN ETAL 3,161,241

ROTARY POWER HAMMER Filed Aug. 8, 1963 3 Sheets-Sheet 3 IIIIIII IO INVENTORS EDWARD L. ALLEN ALBERT F: GATT/KER, JR.

Y 5 QM hiTJAJIJ 34 ATTORNEY United States Patent Ofilice 3,161,241 Patented Dec. 15, 164

3,161,241 RQTARY PSWER HAIVIIWER Edward L. Allen, Ulster, and Albert F. Gattiker, 3n, Athens, Pa., assignors to Ingersoll-Rand Company, New York, N.Y., a corporation of New Jersey Filed Aug. 8, 1963, Ser. No. 300,735 7 Claims. (till. 173--47) This invention relates to portable power tools which rotate and axially hammer tool implements.

The principal object of this invention is to provide a handy portable power tool which will simultaneously rotate and hammer a tool implement and also. selectively rotate the tool implement without hammering it or hammer it without rotating it.

Other important objects of this invention are: to provide a lightweight, inexpensive, and relatively simple power tool impact mechanism; to provide a novel impact mechanism which can be quickly and easily converted from applying axial impacts without rotation to applying axial impacts with rotation; and to provide a new type of power hammer.

In brief, the objects of this invention are provided by driving a pair of carriers through an epicyclic gear train wherein they can be locked against rotation alternately, providing a means for locking the carriers alternately, mounting a mechanism between the carriers to provide a hammering action resulting from relative rotation between the carriers and mounting an implement holder on one of the carriers. When the carrier holding the implement is rotated, the tool simultaneously rotates and hammers the implement. A mere hammering action is obtained when the other carrier is rotated.

The invention is described in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view with portions cut-away of a power tool embodying the principles of'this invention;

FIG. 2 is a perspective and cut-away view of the novel impact mechanism of this invention;

FIGS. 3, 4 and are vertical sections taken along corresponding section lines in FIG. 1; and

FIG. 6 is a fragmentary section of the nose of the tool of FIG. 1 illustrating its use with an alternate tool implement or bit.

The embodiment of the invention illustrated in the drawings includes a pistol-shaped casing or frame 1 including a pistol grip 2 and a head 3. The head 3 con tains a conventional rotary motor (not shown) which may be either an electric motor or a fluid operated motor and is controlled by the trigger 4 mounted on the pistol grip 2. The motor includes a rotor 5 mounted in bearings 6 and carrying a pinion '7 projecting forwardly from it.

An outer cylindrically-shaped hollow carrier 10 is rotatably mounted in the front portion of the head 3 and carries a reduced diameter tubular nose 11 projecting forwardly from the front of the head 3. The carrier 10 is rotatably mounted in needle bearings 12 and is arranged with its rear end engaging a thrust bearing 13.

The nose 11 contains a chuck 14 at its front end adapted to receive the rear end or shank 15 of a work implement 16. The implement 16 may be of various conventional types, depending on the type of work that is desired. For example, it may be an ordinary star drill. The' chuck 14 contains a bore having flat sides and the shank 15 has corresponding fiat sides so that it is locked against rotation in the chuck 14. It will be understood that if circumstances arise where it is undesirable for the implementlto be keyed in the chuck 14,.one can use an im- 'plementfhaving a cylindrical shank.

A second carrier 18 is rotatably mounted in the frame 1 within the outer carrier 10. The second or inner carrier 18 rotates on bearings 19. The inner carrier 18 carries a pair of rotatable planet gears 20 rotating on stub shafts 21 and engaging the rotor pinion 7. The outer carrier 10 is provided with internal gear teeth to form a ring gear 22 engaging the planet gears 20, thus providing an epicyclic gear train.

A pair of brake bands 24 and 25 are mounted around the two carriers 10 and 18 and a selective mechanism 26 is mounted on the frame 1 for alternately tightening the brake bands 24 and 25 around the carriers 10 and 18 whereby one is locked against rotation. One end of each of the brake bands 24 and 25 is attached to an anchor pin 27. The selection mechanism 26 includes a shaft, also designated 26, carrying a handle 28 and a pair of eccentric cams 29 and 30 arranged at to each other to alternately tighten the brake bands 24 and 25 as the handle 28 is swung from side-to-side through a semicircle. The end of each brake band opposite the anchor pin 27 is provided with an eye encircling one of the cams 29 or 30.

It should now be obvious that if either one of the carriers is locked against rotation, the other will be driven by the tool motor through the epicyclic gear train. For example, if the outer carrier 16 is locked, the inner carrier 18 will be driven. Conversely, if the inner carrier is locked, the outer carrier 10 will be driven.

A cup-shaped fiuid compressor piston 32 is reciprocably mounted within the outer carrier 10 and is prevented from rotating in the carrier 10 by having a key 33 fitting in a longitudinal internal key way 34 formed in the interior of the carrier 1%}. The piston 32 contains an internal serpentine-shaped groove 35 encircling it and engaging balls 36 mounted in the periphery of the inner carrier 18 whereby relative rotation between the piston 32 and the inner carrier 18 causes the piston to reciprocate.

The reciprocation of the piston 32 alternately compresses air in the chamber 38 formed in front of it by the enclosing walls of the outer carrier 10. The chamber 38 opens through a port 39 into a smaller chamber 40 formed in the nose 11. A slave piston 41 is slidably mounted in the nose 11 so that it is moved back and forth by the pulsating air column created by the reciprocating compressor piston 32. The front end of the slave piston 41 is adapted to strike percussive or hammer blows to the shank 15 of the work implement 16 as it reciprocates.

The tool is provided with means to prevent the slave piston 41 from reciprocating when a tool implement 16 is withdrawn from the chuck 14. The nose 11 contains a spring 42 for biasing the slave piston 41 forwardly against the chuck 14 when the implement shank 15 is withdrawn from the tool. In this position, the slave piston 41 uncovers an exhaust port 43 for the nose chamber 40, whereby the pulsating air column in the nose.11 is unable to reciprocate the slave piston 41. Also, one can insert an implement 44. into the chuck 14 having a short shank 45 which does not force the slave piston 41 back over the port 43, as shown in FIG. 6. Thus, the implement 44- will rotate without being harnmered.

Operation remains keyed to the outer carrier 18,- the relative rotation between the compressor piston 32 and the inner carrier 18 causes the serpentine cam 35 to reciprocate the piston 32. As a result, the work implement 16 is hammered but is not rotated;

If the operator withdraws the work implement from the chuck 14, the slave piston 41 is moved forwardby the spring 42 to uncover the port 43, thus discharging the pulsations of the compressorpiston32 to atmosphere so that they do not move the slave'piston.

Finally, if a purely rotating motion of the implement is desired, the operator inserts the short shank implement I 44in the chuck 14 and returns the selector lever 28 to the position shown inFiG. 2. Inthis position, the outer carrier 10 rotates the implement 44 while the compressor piston 32 fails to move the slave piston 41, due to the port 43 being open;

Although a preferred embodiment of the invention is illustrated anddescribed in detail, it will be understood that the invention is not limited simply to this embodiment, but contemplates other embodiments and variations which utilize the concepts and teachings "of this invention. s5;

'Havingdescribed ourinvention, we claim: 1. A power impact tool comprising: (a) a frame;

(b) a rotary motor mounted on a pinion; 7 I (c) a first-carrier rotatably supported in said frame; (d) a work implement slidably supported in said first carrier andadapted to receive periodic axial ham: mer blows; 1 Y (e) a piston reciprocably (f) means'for transmitting the reciprocation ot' said piston to said-work implement as a series of hammer blows; V (g) a second carrier rotatably mounted in said frame; (12) an epicyclic gear train interconnecting said Ifirst and second carriers to said p inion including a first gear fixed on one carrier and a second gear rotatably mounted on the other-carrier; i

(i) cam means engaged between one of said carriers .and said piston for 'reciprocatingjsaid piston when relativerotation occurs between that carrier and said piston;

(i) key means locking said piston to the carrier which 7 V does not engage saidcam means to prevent relative 1T;- y BRoUGHTO N G. DURHAM, Primary Examiner.-

said frame and driving 7 mounted in said first carrier;

7 UNlTEDSTAT-ES PATENTS 2,531,842 1 1/50 Karleen V I, 74-57 3,114,421 12/63-'McClou,d ..f1' 73-14' a rotation therebetween while allowing the piston to reciprocate; and

(k) means for selectively locking either one of said carriers to said frame to prevent it from rotating whereby said work implement selectively can be simultaneously rotated and hammered or hammered without being rotated.

2. The impact tool of claim 1 wherein:

(a) said piston is slidably keyed to said first carrier;

and

(b) said cam means is engaged between said piston and said second carrier.

3. The impact tool of claim' 2 wherein:

(a) said first carrier has a hollow sleeve shape and in: cludesa reduced diameter nose carrying a chuck for holding the work implement; v

(b) said second carrier is of a cylindrical shape and is rotatably mounted within said first carrier; and

.(c) said piston is' slidably mounted between said first v and second carriers and rides in both carriers. 4. The impact tool of claim 3 Whereint.

(a) said means .for selectively locking said carriers includes a pair of brake bands with one .band engaging eachcarrier; and

(b) cam means which can be moved between two posi-,- tions wherein each of said brake bands is alternately tightened on its engaging carrier as said cam means is moved to said two positions.

. 5. The impact tool of claim 4 wherein said first carrier isrotatably mounted on twosets of bearings, one adapted to withstand radial loads and the other. adapted to with stand rearwardly acting axial loads.

6. The impact tool of claim 4 wherein saidmeans for transmitting the reciprocation of said piston to said work 35 implement'as a series. of hammer blows includes a second piston slidably mounted in the nose of said firstcarrier and adapted-to be reciprocated by pulsationsprovided by the reciprocation of 'the first'mentioned'piston, said sec- 0nd piston being arranged to strike-said work implement as it'moves forward. a i

7. The impacttool of 'claim:f6 wherein: I (a) said secondpiston is biased forwardly bya spring;

(b) said nose of said firstcarrier is provided with. a port to exhaust the rear end of said second piston to atmosphere wheniit is moved forwardly to the limit of'itstravel;

ReferencesCited by the Examiner" 

1. A POWER IMPACT TOOL COMPRISING: (A) A FRAME; (B) A ROTARY MOTOR MOUNTED ON SAID FRAME AND DRIVING A PINION; (C) A FIRST CARRIER ROTATABLY SUPPORTED IN SAID FRAME; (D) A WORK IMPLEMENT SLIDABLY SUPPORTED IN SAID FIRST CARRIER AND ADAPTED TO RECEIVE PERIODIC AXIAL HAMMER BLOWS; (E) A PISTON RECIPROCABLY MOUNTED IN SAID FIRST CARRIER; (F) MEANS FOR TRANSMITTING THE RECIPROCATION OF SAID PISTON TO SAID WORK IMPLEMENT AS A SERIES OF HAMMER BLOWS; (G) A SECOND CARRIER ROTATABLY MOUNTED IN SAID FRAME; (H) AN EPICYCLIC GEAR TRAIN INTERCONNECTING SAID FIRST AND SECOND CARRIERS TO SAID PINION INCLUDING A FIRST GEAR FIXED ON ONE CARRIER AND A SECOND GEAR ROTATABLY MOUNTED ON THE OTHER CARRIER; (I) CAM MEANS ENGAGED BETWEEN ONE OF SAID CARRIERS AND SAID PISTON FOR RECIPROCATING SAID PISTON WHEN RELATIVE ROTATION OCCURS BETWEEN THAT CARRIER AND SAID PISTON; (J) KEY MEANS LOCKING SAID PISTON TO THE CARRIER WHICH DOES NOT ENGAGE SAID CAM MEANS TO PREVENT RELATIVE ROTATION THEREBETWEEN WHILE ALLOWING THE PISTON TO RECIPROCATE; AND (K) MEANS FOR SELECTIVELY LOCKING EITHER ONE OF SAID CARRIERS TO SAID FRAME TO PREVENT IT FROM ROTATING WHEREBY SAID WORK IMPLEMENT SELECTIVELY CAN BE SIMULTANEOUSLY ROTATED AND HAMMERED OR HAMMERED WITHOUT BEING ROTATED. 